South American geopolitcs follows a different path with respect to its American or European versions. The latter explore in particular its contribution to the theory of «living space» (lebensraum) and the expansionist wars fought by Nazi Germany. For this reason, after the Second world war, western democracies set geopolitics aside. In South America geopolitics had arrived in the Thirties and the article examines nazi propaganda which, drawing on geopolitical arguments, aimed to create a «Deutsch Südamerika», starting from German colonies in Argentina and southern Brazil. The most relevant Brazilian figures who kept on cultivating geopolitics during the Cold war and military dictatorship are analyzed. Geopolitics was used, for example, in the fight for the supremacy over South America which involved Argentina and Brazil, in the debate over the internationalization of the Amazon, in the plans for the control of Antarctica. Geopolitics has now partly gone back to being a scientific discipline in the West, anyhow it has to be kept under observation as it tends to be used by politicians and generals to advance territorial claims which may lead to international crises, and even open armed conflicts.